6 BULLETIN 696, U. S. DEPARTMENT OF AGRICULTURE. 
cally the entire gross surplus of the country. All other sections pro- 
duce less than their requirements. In the Great Plains and west- 
ward — nearly half the total land area — hardly 2 per cent of the 
national harvest is produced. 
While low price levels rule throughout the surplus-producing area, 
cheapest corn has been observed within its northwestern corner. This 
part is most disadvantageous^ situated with regard to the important 
domestic and foreign markets, which lie to the East and South. 
From the centrally located corn belt the product moves to practically 
all points of the compass, since all other sections must supplement 
local crops by shipments from this territory. Likewise, prices mount 
in the direction of this flow, attaining steadily higher levels toward 
the areas which (subject to the modifications of local conditions) are 
most distant from the regions of surplus corn. Distance or length 
of haul in this sense is taken to represent differences in transporta- 
tion costs, in which it is ordinarily the chief factor. Other items of 
distributive expense are usually measured in fractions of a cent per 
bushel, and vary but little with distance. 
PREDOMINANT TRADE ROUTES AND PRICE LEVELS, AND LOCAL 
VARIATION. 
In the prevailing drift of the price levels a considerable degree of 
local variation may be seen. Such differences, which are to some 
extent observable on Map 1, are shown more clearly in a later de- 
tailed map. Thus the upgrade — from the pivotal area of lowest 
price in the corn belt — is slower in some directions than in others. 
It is slower throughout the sections where the traffic moves in greatest 
volume or where large local supplies are available — eastward across 
the North Central States ; the upgrade becomes more rapid through 
regions of scant production or of relatively little consumption — west- 
ward, for instance. Aside from this irregular increase, many areas 
appear wherein prices paid to farmers are considerably higher or 
lower than in the surrounding regions. 
The manifold uses of grain, plant and cob, as well as the conditions 
surrounding the distribution of the corn crop, result in a somewhat 
intricate commercial and price movement. To account for the drift 
of the price levels it is necessary to consider, briefly, a few interna- 
tional as well as domestic phases of the commerce in corn. To ac- 
count for local variations it is necessary to consider such local fac- 
tors as differences in costs of transportation by wagon, rail or water, 
rural roads, accessibility of markets, the volume and organization of 
the traffic as shown in elevating, and market facilities. 
